Signaling apparatus



March 15, 1955 .R: L. BARR 2,704,359

SIGNALING APPARATUS Filed Dec. 10, 1951 2 Sheets-Sheet 1 H C SOURCEINVENTOR.

ROBERT L. BARR BY W WIZ/MW ATTORNEY March 15, 1955 R. L. BARR 2,704,359

SIGNALING APPARATUS Filed DeclO, 1951 2 Sheets-Sheet 2 FIG. 2.

ROBERT L. BARR ATTORNEY United States Patent SIGNALING APPARATUS RobertL. Barr, Libertyville, Ill., assignor to Raytheon Manufacturing Company,a corporation of Illinois Application December 10, 1951, Serial No.260,870

6 Claims. (Cl. 340-25) The present invention relates in general to asignaling apparatus, and more particularly to a signaling apparatushaving a gaseous electric discharge device.

In airplane guiding light systems of the type wherein a single lightbeacon would oscillate from two angular positions, a concentrated lightsource, as well as a modulated light source, is needed to enable a pilotto determine whether the airplane is on course, or in a common area ofthe light beam. When the airplane is flying on course the pilot receivesa continuous signal, whereas, if the airplane were flying to the rightof the common area, the pilot would receive one signal and, if theairplane were flying to the left of the common area, the pilot wouldreceive another signal.

Signaling apparatus of the type adaptable for use as an airplane guidinglight beacon may use any suitable arc tube, such as a cesium arc tube,which produces divergent light rays regardless of the type of reflectorused in conjunction therewith. This factor is prevalent in the use ofgaseous discharge lamps, since they do not lend themselves to functionas a point source of light. To produce a point source of light, it isdesirable to use an incandescent filament light source. However, theincandescent filament light source, such as the concentrated tungstenfilament, cannot be modulated in the event voice modulation becomesnecessary.

Accordingly, an important object of the present invention is to providea signaling apparatus that at times provides a modulating light sourceand at other times provides a narrow angular light beam.

Another object of the present invention is to provide a signalingapparatus having a gaseous electric discharge device for providing attimes a modulating light source and an incandescent filament in saiddischarge device to provide at other times a narrow beam of light.

Another object of the present invention is to provide a signalingapparatus wherein a gaseous electric discharge device provides at timesa modulated light source, and an incandescent filament in said gaseousdischarge device positioned at the focal point of a reflector providesat other times a concentrated light source having a narrow beam width.

Other objects will appear upon a further perusal of the detaileddescription taken in conjunction with the accompanying drawings inwhich:

Figure 1 is a partial schematic diagram of the signaling appaartusembodying the present invention; and

Figure 2 is a partial schematic diagram of a modification of thesignaling apparatus embodying the present invention.

Briefly described, the signaling apparatus of the present inventioncomprises a gaseous electric discharge device suitably positioned at thebase thereof at the apex or any other suitable place of a suitablereflector member, which in the preferred embodiment is a parabolicreflector. The gaseous electric discharge device comprises an outerenvelope and an inner envelope, and in the preferred embodiment havingtherebetween a vacuous area. The inner envelope contains a glowdischarge vapor or gas, such as cesium vapor or gas, and in conjunctiontherewith suitable means to produce the arc glow in order to provide alight source capable of modulation.

According to the invention, in order to provide a point source of light,an incandescent filament, such as a tungsten filament is positionedwithin the inner envelope of a gaseous electric discharge device.

In the modification, the incandescent filament is placed ice in thevacuous area between the inner and outer envelopes. To provide a narrowangular light beam, thereby lessening divergent rays of light, theincandescent filament is placed at the focal point of the suitablereflector member.

In order to provide a signaling apparatus wherein at times the gaseouselectric discharge device provides themodulated light source, and atother times the incandescent filament in said gaseous electric dischargedevice provides a point source of light, circuit means are provided forat times energizing suitable means to ionize the vapor or gas, and atother times energizing the incandescent filament. The incandescentfilament, when desired, can be utilized in addition to the functionsheretofore mentioned for maintaining the vapor ionized when the starterelectrodes are deenergized.

Referring now to Figures 1 and 2, a signaling apparatus 10 is providedadaptable for use in airplane beacon systems having a single lightbeacon which oscillates between two angular positions. The signalingapparatus comprises a gaseous electric discharge device 11, which in thepreferred embodiment is a cesium arc lamp.

The gaseous electric discharge device 11 comprises an outer envelope 12of a suitable type, size and shape, which is supported by a conventionalor any suitable base 13. Within the neck of the outer envelope 12 issealed a stem or standard which constitutes the usual means forintroducing support wire conductors 14-18, inclusive, into the innerenvelope 20. For supporting the various elements within the outerenvelope 12, the support wires 14-18 are provided.

Referring more particularly to Figure 2, there is shown an innerenvelope 20a, similar to inner envelope 20, except that a narrow neckportion 20b is provided at the central portion thereof for reasons to bedescribed hereinafter. The inner envelope 20a is supported in a mannersimilar to that for the supporting of inner envelope 20.

The inner envelope 20, as well as the inner envelope 20a, contains asuitable means for ionizing gas or vapor, such as a pair of are orstarter electrodes 21 and 22 at the opposite ends thereof. The starterelectrode 21 is supported within the inner envelope 20, as well as innerenvelope 20a, by means of the support wire conductors 14 and 15. Thestarter electrode 22 is supported within the inner envelope 20, as wellas inner envelope 20a, by means of support wire conductors 16 and 17.The support wire conductors 14 and 15 are suitably received through theinner envelope 20, as well as inner envelope 200, by any conventional orsuitable means for establishing electrical connections to the pair ofarc electrodes 21 and 22, such as a sealed stem or a fused stem.

In order to provide a source of light capable of modulation, the starterelectrodes 21 and 22 establish an arc in the inner envelope 20, as wellas the inner envelope 20a, in an atmosphere of suitable gas or vapor,which in the preferred embodiment is a cesium gas or vapor. In thepreferred embodiment, a vacuous state is provided between the outerenvelope 12 and the inner envelope 20, as well as the inner envelope20a.

For concentrating the ray of light emitted, a suitable reflector member23 is associated with the gaseous discharge device 11 at the baseportion 13 thereof. In the preferred embodiment, the reflector 13 is aparabolic reflector which has a suitable opening 24 at the apex thereoffor receiving the base 13 of the gaseous discharge device 11 Forestablishing electrical connections from the gaseous discharge device,the support wire conductors 14-18, inclusive, are fused or pressed at astem in the gaseous discharge device 11 contained in the base 13 in awellknown manner. Prongs 25-30, inclusive, are secured to the base 13and are electrically connected to the support wire conductors 14-18,inclusive, in any suitable manner for establishing electricalconnections from the gaseous discharge device 11 to an external circuit.

According to the invention, in order to provide a point source of light,an incandescent filament 31 is provided, which in the preferredembodiment is a tungsten filament. The incandescent filament 31 issupported within the inner envelope 20 by means of the support wireconductors 18 and 19 at the focal point of the reflector memher 23. Thesupport wire conductors 18 and 19 are received by the inner envelope 20by means such as a sealed or fused stem.

Referring more particularly to the modification shown in Figure 2, anincandescent filament 31a is provided, which in the preferred embodimentis a tungsten filament. The incandescent filament 31 is supported bymeans of the support wires 18 and 19 at the focal point of the reflectormember 23.

In order to increase the operating time of the incandescent filament,the incandescent filament is wound in a spiral configuration, such ascoil form, encompassing the narrow neck portion 20b of the innerenvelope 20a, thereby being positioned in the vacuous area and also atthe focal point of the reflector member 23.

It is to be noted that in airplane signaling systems, particularly ofthe type using a single light beacon that oscillates between two angularpositions, a signaling apparatus is required that at times would providea modulated light source and at other times would provide a narrowangular beam for spotting or aiming. The electric discharge device, suchas a cesium arc lamp, emits divergent rays even when used in conjunctionwith a reflector member. This is caused by the fact that a gaseousdischarge device provides a wide source of light and therefore, whenreflected, the rays have angular dispersions of light and are notparallel to one another. The airplane light beacons require at times anarrow angular light beam, which cannot be had when using a gaseouselectric discharge device, such as a cesium arc lamp. A point source oflight, when reflected, provides rays that are substantially parallel toone another, and therefore not divergent. An incandescent filament, suchas a tungsten filament provides a point source of light, but theincandescent filament cannot be modulated, when audio modulation isrequired for providing coded signals. By placing the incandescentfilament at the focal point of the reflector member, such as a parabolicreflector, and in the gaseous electric discharge device, the beam oflight becomes a concentrated angular light beam.

Accordingly, circuit means 32 are herein provided to at times energizethe incandescent filament to provide a point source of light and atother times to energize the suitable means, such as starter electrodes21 and 22, to ionize the vapor or gas contained in the inner envelope 20or 20a, and in addition thereto modulate the light emitted thereby toprovide a modulated light source. In addition to the foregoing, at stillother times the vapor or gas contained in the inner envelope is ionizedby the potential on the arc electrodes in order to provide a modulatedlight source and the incandescent filament is en ergized to maintain thegas or vapor energized in the event the starter electrodes 21 and 22 aredeenergized or become extinguished.

The circuit means 32 comprises terminals 33 and 34 which are connectedto a suitable source of alternating current. Connected to thealternating current source by way of terminals 33 and 34 is a suitabletransformer 35 to provide a suitable voltage for heating theincandescent filament 31, and similarly 31a.

For heating the filaments of the starter electrodes 21 and 22,transformer 36 is connected to the alternating current source by way ofthe terminals 33 and 34. A suitable starting switch 37 is provided tocontrol the applicatiocrll 22f the filament voltage to the starterelectrodes 21 an For supplying the firing potential to the startingelectrodes 21 and 22, a suitable direct current source is provided, suchas direct current generator 38. Connected in series therewith is aballast 39, which limits the load on the generator 38 once the gas orvapor contained in the inner envelope 20 or 20a becomes ionized. Whilethe preferred embodiment shows the filament being heated by analternating current, it is to be understood that a direct current sourcecan be used equally as well. Further, it is to be understood that,although the electric discharge are is shown operating on a directcurrent, it can be operated equally as well on an alternating currentover a wide range of frequencies.

In order to provide a modulating potential, at suitable modulating unit40 is provided, which can be any conventional unit, well known in theart of voice modulation. Connected in series therewith is a blockingcondenser 41 to prevent the direct current from flowing into themodulating unit. The modulating voltage is superimposed on the directcurrent potential for energizing the arc electrodes 21 and 22. Forcontrolling the operation of the circuit 32, a suitable three-positionswitch 42 is provided having two contact arms 43 and 44 operatedsimultaneously.

In operation, in order to provide at times the narrow angular light beamby energizing the incandescent filament 31 or 31a, the switch 42 isactuated to place the contact arms 43 and 44 on contact 1. Thereupon,the incandescent filament 31 or 31a is energized over the followingpath: terminals 33 and 34, transformer 35, con tact arm 43, prongs 26and 29, conductors 18 and 19, and filament 31 or 3111. Since contact 1for contact arm 44 is an open terminal there is no continuity throughcontact arm 44 to energize the starter electrodes 21 and 22.

In order to provide at other times a modulated light source by ionizingthe gas or vapor contained in the inner envelope 20 or 20a, the switch44 is actuated to place the contact arms 43 and 44 on contacts 3. Beforethe actuation of the switch 42, it is conventional to close starterswitch 37 to energize the filaments of the starter electrodes 21 and 22.The filament of starter electrode 21 is energized over the followingpath: terminals 33 and 34, switch 37, transformer 36, prongs 25 and 28,con ductors 14 and 15, and starter electrode 21. The filament of starterelectrode 22 is energized over the following path: terminals 33 and 34,switch 37, transformer 36, prongs 27 and 30, conductors 16 and 17, andstarter electrode 22.

A direct current potential is applied to the starter electrodes 21 and22 to ionize the gas or vapor contained in the inner envelope 20 or 20aover the following path: electrode 21, conductors 14 and 15, prongs 25and 28, secondary winding 36a, ballast 39, D. C. generator 38, contact3, contact arm 44, secondary winding 36b, prongs 27 and 30, conductors16 and 17, and electrode 22.

For modulating the are glow, the potential on the electrodes 21 and 22is varied over the following path: electrode 21, conductors 14 and 15,prongs 25 and 28, secondary winding 36a, condenser 41, modulating unit40, secondary winding 36b, prongs 27 and 30, conductors 16 and 17 andelectrode 22.

Since contact 3 for contact arm 43 is an open terminal, there is nocontinuity through contact arm 43 to energize the incandescent filament31 or 31a.

In order to provide at still other times a modulated light source byionizing the gas or vapor contained in the inner envelope 20 or 20a, andin addition thereto use the incandescent filament 31 or 31a formaintaining the gas or vapor contained in the inner envelope 20 or 20aionized in the event the starter electrodes 21 and 22 are deenergized orextinguished, switch 42 is actuated to place the contact arms 43 and 44on contacts 2. The operation of the circuit is similar to thatpreviously described in that the operation is a combination of theoperations previously described when the contact arms 43 and 44 wereengaging contacts 1 and 3.

It is to be understood that variations and modifications may be effectedwithout departing from the scope of the appended claims.

I claim:

1. In a signaling system, a gaseous electric discharge device, anenvelope in said discharge device containing gas to provide an arc glow,a first means for ionizing the gas contained therein, an incandescentfilament in said envelope for providing a point source of light, a firstcircuit for energizing said incandescent filament to provide a pointsource of light, a second circuit for energizing said first means toprovide an arc glow, a modulating unit connected to said second circuitfor superimposing voice modulating signals thereon to provide a voicemodulated light source, and a switching circuit operated at times forconnecting said first circuit to said incandescent filament to provide apoint source of light and operated at other times to connect said secondcircuit to said first means to provide a voice modulated light source.

2. In a signaling system, a gaseous discharge device, an envelope insaid discharge device containing gas to provide an arc glow, a firstmeans in said envelope for ionizing the gas therein, a reflector memberencompassing a portion of said device for directing light rays, anincandescent filament in said envelope for providing a point source oflight and positioned at the focal point of said reflector member forconcentrating the light rays emittable thereby, a first circuit forenergizing said in candescent filament to provide a point source oflight, a second circuit for energizing said first means to provide anarc glow, a modulating unit connected to said second circuit forsuperimposing voice modulating signals thereon to provide a voicemodulated light source, and a switching circuit operated at times forconnecting said first circuit to said incandescent filament to provide apoint source of light and operated at other times to connect said secondcircuit to said first means to provide a voice modulated light source.

3. In a signaling system, a cesium arc lamp, an envelope in said arelamp containing gas to provide an arc glow, a first means in saidenvelope for ionizing the gas therein, a reflector member encompassing aportion of said lamp for directing light rays, a tungsten filament insaid envelope for providing a point source of light and positioned atthe focal point of said reflector member for concentrating the lightrays emittable thereby, a first circuit for energizing said tungstenfilament to provide a point source of light, a second circuit forenergizing said first means to provide an arc glow, a modulating unitconnected to said second circuit for superimposing voice modulatingsignals thereon to provide a voice modulated light source, and aswitching circuit operated at times for connecting said first circuit tosaid tungsten filament to provide a point source of light and operatedat other times to connect said second circuit to said first means toprovide a voice modulated light source.

4. In a signaling system, a cesium arc lamp, an envelope in said arelamp containing gas to provide an arc glow, a first means in saidenvelope forionizing the gas therein, a reflector member encompassing aportion of said lamp for directing light rays, a tungsten filament insaid cesium arc lamp for providing a point source of light andpositioned at the focal point of said reflector member for concentratingthe light rays emittable thereby, a first circuit for energizing saidtungsten filament to provide a point source of light, a second circuitfor energizing said first means to provide an arc glow, a modulatingunit connected to said second circuit for superimposing voice modulatingsignals thereon to provide a voice modulated light source, and aswitching circuit operated at times for connecting said first circuit totungsten filament to provide a point source of light and operated atother times to connect said second circuit to said first means toprovide a voice modulated light source.

5. In a signaling system, a cesium arc lamp, an envelope in said arelamp containing gas to provide an arc glow, a first means in saidenvelope for ionizing the gas therein, an incandescent filament in saidcesium arc lamp to provide a point source of light, a first circuit forenergizing said incandescent filament to provide a point source oflight, a second circuit for energizing said first means to provide anarc glow, a modulating unit connected to said second circuit forsuperimposing voice modulating signals thereon to provide a voicemodulated light source, and a switching circuit operated at times forconnecting said first circuit to said incandescent filament to provide apoint source of light and operated at other times to connect said secondcircuit to said first means to provide a voice modulated light source.

6. In a signaling system, a cesium arc lamp, an envelope in said arelamp containing gas to provide an arc glow, a first means in saidenvelope for ionizing the gas therein, a reflector member encompassing aportion of said lamp for directing light rays, an incandescent filamentin said cesium arc lamp for providing a point source of light andpositioned at the focal point of said reflector member for concentratingthe light rays emittable thereby, a first circuit for energizing saidincandescent filament to provide a point source of light, a secondcircuit for energizing said first means to provide an arc glow, amodulating unit connected to said second circuit for superimposing voicemodulating signals thereon to provide a voice modulated light source,and a switching circuit operated at times for connecting said firstcircuit to said incandescent filament to provide a point source of lightand operated at other times to connect said second circuit to said firstmeans to provide a voice modulated light source.

References Cited in the file of this patent UNITED STATES PATENTS1,905,267 Corey Apr. 25, 1933 2,097,261 Spanner Oct. 26, 1937 2,171,580Macksoud Sept. 5, 1939 2,487,734 Seaman Nov. 8, 1949

